Just a few months after the market launch of its new El-Exis SP (Speed Performance) series at the K 2010, Sumitomo (SHI) Demag Plastics Machinery GmbH, is conquering the high-speed applications of the packaging industry. The enhanced hybrid machine is already demonstrating its advantages in terms of dynamics and efficiency. The El-Exis SP is impressive in the high-speed production of thin-walled food packaging, caps and closures for drinks, cartridges, flower pots and buckets.
"We're pleased that not only existing El-Exis S customers have switched over to the new El-Exis SP technology, but that we have also convinced new customers of the benefits of our machine," emphasises Christian Renners, General Manager of the Sales & After Sales Business Unit at Sumitomo (SHI) Demag. "Although the El-Exis S has already made its name as a racer in the packaging industry, its enhancement in the form of the El-Exis SP is another quantum leap with regard to cycle time," he continues. "With the new series we have tested the limits in the production of packaging while maintaining stable processes."
The series has been gradually expanded since its premiere at the K 2010 and with models in eight sizes already covers a clamping force range of 2,000 to 7,500 kN. In the fourth quarter of 2011 a 1,500 kN model will complete the series which is to encompass nine sizes. It must be particularly emphasised that the new models from 3,000 kN already offer an enlarged opening stroke for the toggle-type clamping unit as a standard feature. With the generous dimensions of the mould mounting space, Sumitomo (SHI) Demag offers manufacturers of larger containers like buckets and cartridges greater choice when selecting a model.
Robust high-speed models make full use of potential
With the development of its high-end, high-speed models Sumitomo (SHI) Demag is delivering exactly what packaging manufacturers need. Their main concerns are low unit costs, the maximisation of output and cost effectiveness. With the extremely short cycle times usual in the production of packaging, cycles that are just a few tenths of a second shorter represent a significant increase in productivity.
"When designing the new El-Exis SP series, the idea was to squeeze out the last tenths of a second, to make the injection moulding machine even more dynamic and faster and to produce parts with even thinner walls," says Bernd Tröger, Head of Product Management at Sumitomo (SHI) Demag, describing the task at hand. So the El-Exis SP opens up completely new areas of application for injection moulding which were once reserved for thermoforming. "Thermoforming was previously seen as the faster and more cost effective process. But with the El-Exis SP even thin-walled disposable containers can be produced economically using injection moulding processes," says Bernd Tröger with conviction.
This is also associated with a particular requirement regarding the robustness of the machines. "These machines have a cycle time of 2 to 3 seconds. During its lifetime, a high-speed machine passes through an immense number of cycles. A central point of the development was therefore to achieve a high degree of availability, despite the request for extreme performance data for producers of packaging," explains Bernd Tröger. With the El-Exis SP the manufacturer has adhered to the El-Exis drive philosophy that has proven its worth in more than 1,000 machines: The hybrid, high-performance machine has an electric drive for the rotate movement, an electro-hydraulic drive for the mould opening and a hydraulic accumulator for the injection movement. All secondary movements of the El-Exis SP are hydraulically controlled through a servo valve technique.
El-Exis SP for more dynamic mould movements
The main focus of the speed-performance model was the optimisation of the mould movement. In high-speed production the opening and closing of the mould can account for as much as 60 % of the total cycle time. Due to this dominant effect, simply increasing the speed of the mould movements can result in productivity increases of high single-digit percentages. The electro-hydraulic assembly driving the five-point double toggle of the El-Exis SP is a combination of a servo motor and a hydrostatic gear for the transmission of the motor rotation to the hydraulic linear movement. Improvements to the control behaviour of the motor and the optimised layout of the hydraulics and the valves mean that the El-Exis SP now has a more dynamic clamping unit with faster travel speeds and greater positioning accuracy.
